<?php

namespace GetId3\Module\Graphic;

use GetId3\Handler\BaseHandler;
use GetId3\Lib\Helper;

/////////////////////////////////////////////////////////////////
/// GetId3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
//                                                             //
// module.graphic.bmp.php                                      //
// module for analyzing BMP Image files                        //
// dependencies: NONE                                          //
//                                                            ///
/////////////////////////////////////////////////////////////////

/**
 * module for analyzing BMP Image files
 *
 * @author James Heinrich <info@getid3.org>
 *
 * @link http://getid3.sourceforge.net
 * @link http://www.getid3.org
 */
class Bmp extends BaseHandler
{
    /**
     * @var false
     */
    public $ExtractPalette = false;
    /**
     * @var false
     */
    public $ExtractData = false;

    /**
     * @return bool
     */
    public function analyze()
    {
        $info = &$this->getid3->info;

        // shortcuts
        $info['bmp']['header']['raw'] = array();
        $thisfile_bmp = &$info['bmp'];
        $thisfile_bmp_header = &$thisfile_bmp['header'];
        $thisfile_bmp_header_raw = &$thisfile_bmp_header['raw'];

        // BITMAPFILEHEADER [14 bytes] - http://msdn.microsoft.com/library/en-us/gdi/bitmaps_62uq.asp
        // all versions
        // WORD    bfType;
        // DWORD   bfSize;
        // WORD    bfReserved1;
        // WORD    bfReserved2;
        // DWORD   bfOffBits;

        fseek($this->getid3->fp, $info['avdataoffset'], SEEK_SET);
        $offset = 0;
        $BMPheader = fread($this->getid3->fp, 14 + 40);

        $thisfile_bmp_header_raw['identifier'] = substr($BMPheader, $offset, 2);
        $offset += 2;

        $magic = 'BM';
        if ($thisfile_bmp_header_raw['identifier'] != $magic) {
            $info['error'][] = 'Expecting "'.Helper::PrintHexBytes($magic).'" at offset '.$info['avdataoffset'].', found "'.Helper::PrintHexBytes($thisfile_bmp_header_raw['identifier']).'"';
            unset($info['fileformat']);
            unset($info['bmp']);

            return false;
        }

        $thisfile_bmp_header_raw['filesize'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
        $offset += 4;
        $thisfile_bmp_header_raw['reserved1'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
        $offset += 2;
        $thisfile_bmp_header_raw['reserved2'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
        $offset += 2;
        $thisfile_bmp_header_raw['data_offset'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
        $offset += 4;
        $thisfile_bmp_header_raw['header_size'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
        $offset += 4;

        // check if the hardcoded-to-1 "planes" is at offset 22 or 26
        $planes22 = Helper::LittleEndian2Int(substr($BMPheader, 22, 2));
        $planes26 = Helper::LittleEndian2Int(substr($BMPheader, 26, 2));
        if (($planes22 == 1) && ($planes26 != 1)) {
            $thisfile_bmp['type_os'] = 'OS/2';
            $thisfile_bmp['type_version'] = 1;
        } elseif (($planes26 == 1) && ($planes22 != 1)) {
            $thisfile_bmp['type_os'] = 'Windows';
            $thisfile_bmp['type_version'] = 1;
        } elseif ($thisfile_bmp_header_raw['header_size'] == 12) {
            $thisfile_bmp['type_os'] = 'OS/2';
            $thisfile_bmp['type_version'] = 1;
        } elseif ($thisfile_bmp_header_raw['header_size'] == 40) {
            $thisfile_bmp['type_os'] = 'Windows';
            $thisfile_bmp['type_version'] = 1;
        } elseif ($thisfile_bmp_header_raw['header_size'] == 84) {
            $thisfile_bmp['type_os'] = 'Windows';
            $thisfile_bmp['type_version'] = 4;
        } elseif ($thisfile_bmp_header_raw['header_size'] == 100) {
            $thisfile_bmp['type_os'] = 'Windows';
            $thisfile_bmp['type_version'] = 5;
        } else {
            $info['error'][] = 'Unknown BMP subtype (or not a BMP file)';
            unset($info['fileformat']);
            unset($info['bmp']);

            return false;
        }

        $info['fileformat'] = 'bmp';
        $info['video']['dataformat'] = 'bmp';
        $info['video']['lossless'] = true;
        $info['video']['pixel_aspect_ratio'] = (float) 1;

        if ($thisfile_bmp['type_os'] == 'OS/2') {

            // OS/2-format BMP
            // http://netghost.narod.ru/gff/graphics/summary/os2bmp.htm

            // DWORD  Size;             /* Size of this structure in bytes */
            // DWORD  Width;            /* Bitmap width in pixels */
            // DWORD  Height;           /* Bitmap height in pixel */
            // WORD   NumPlanes;        /* Number of bit planes (color depth) */
            // WORD   BitsPerPixel;     /* Number of bits per pixel per plane */

            $thisfile_bmp_header_raw['width'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
            $offset += 2;
            $thisfile_bmp_header_raw['height'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
            $offset += 2;
            $thisfile_bmp_header_raw['planes'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
            $offset += 2;
            $thisfile_bmp_header_raw['bits_per_pixel'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
            $offset += 2;

            $info['video']['resolution_x'] = $thisfile_bmp_header_raw['width'];
            $info['video']['resolution_y'] = $thisfile_bmp_header_raw['height'];
            $info['video']['codec'] = 'BI_RGB '.$thisfile_bmp_header_raw['bits_per_pixel'].'-bit';
            $info['video']['bits_per_sample'] = $thisfile_bmp_header_raw['bits_per_pixel'];

            if ($thisfile_bmp['type_version'] >= 2) {
                // DWORD  Compression;      /* Bitmap compression scheme */
                // DWORD  ImageDataSize;    /* Size of bitmap data in bytes */
                // DWORD  XResolution;      /* X resolution of display device */
                // DWORD  YResolution;      /* Y resolution of display device */
                // DWORD  ColorsUsed;       /* Number of color table indices used */
                // DWORD  ColorsImportant;  /* Number of important color indices */
                // WORD   Units;            /* Type of units used to measure resolution */
                // WORD   Reserved;         /* Pad structure to 4-byte boundary */
                // WORD   Recording;        /* Recording algorithm */
                // WORD   Rendering;        /* Halftoning algorithm used */
                // DWORD  Size1;            /* Reserved for halftoning algorithm use */
                // DWORD  Size2;            /* Reserved for halftoning algorithm use */
                // DWORD  ColorEncoding;    /* Color model used in bitmap */
                // DWORD  Identifier;       /* Reserved for application use */

                $thisfile_bmp_header_raw['compression'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['bmp_data_size'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['resolution_h'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['resolution_v'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['colors_used'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['colors_important'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['resolution_units'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
                $offset += 2;
                $thisfile_bmp_header_raw['reserved1'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
                $offset += 2;
                $thisfile_bmp_header_raw['recording'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
                $offset += 2;
                $thisfile_bmp_header_raw['rendering'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
                $offset += 2;
                $thisfile_bmp_header_raw['size1'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['size2'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['color_encoding'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['identifier'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;

                $thisfile_bmp_header['compression'] = $this->BMPcompressionOS2Lookup($thisfile_bmp_header_raw['compression']);

                $info['video']['codec'] = $thisfile_bmp_header['compression'].' '.$thisfile_bmp_header_raw['bits_per_pixel'].'-bit';
            }
        } elseif ($thisfile_bmp['type_os'] == 'Windows') {

            // Windows-format BMP

            // BITMAPINFOHEADER - [40 bytes] http://msdn.microsoft.com/library/en-us/gdi/bitmaps_1rw2.asp
            // all versions
            // DWORD  biSize;
            // LONG   biWidth;
            // LONG   biHeight;
            // WORD   biPlanes;
            // WORD   biBitCount;
            // DWORD  biCompression;
            // DWORD  biSizeImage;
            // LONG   biXPelsPerMeter;
            // LONG   biYPelsPerMeter;
            // DWORD  biClrUsed;
            // DWORD  biClrImportant;

            // possibly integrate this section and module.audio-video.riff.php::ParseBITMAPINFOHEADER() ?

            $thisfile_bmp_header_raw['width'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4), true);
            $offset += 4;
            $thisfile_bmp_header_raw['height'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4), true);
            $offset += 4;
            $thisfile_bmp_header_raw['planes'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
            $offset += 2;
            $thisfile_bmp_header_raw['bits_per_pixel'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 2));
            $offset += 2;
            $thisfile_bmp_header_raw['compression'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
            $offset += 4;
            $thisfile_bmp_header_raw['bmp_data_size'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
            $offset += 4;
            $thisfile_bmp_header_raw['resolution_h'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4), true);
            $offset += 4;
            $thisfile_bmp_header_raw['resolution_v'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4), true);
            $offset += 4;
            $thisfile_bmp_header_raw['colors_used'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
            $offset += 4;
            $thisfile_bmp_header_raw['colors_important'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
            $offset += 4;

            $thisfile_bmp_header['compression'] = $this->BMPcompressionWindowsLookup($thisfile_bmp_header_raw['compression']);
            $info['video']['resolution_x'] = $thisfile_bmp_header_raw['width'];
            $info['video']['resolution_y'] = $thisfile_bmp_header_raw['height'];
            $info['video']['codec'] = $thisfile_bmp_header['compression'].' '.$thisfile_bmp_header_raw['bits_per_pixel'].'-bit';
            $info['video']['bits_per_sample'] = $thisfile_bmp_header_raw['bits_per_pixel'];

            if (($thisfile_bmp['type_version'] >= 4) || ($thisfile_bmp_header_raw['compression'] == 3)) {
                // should only be v4+, but BMPs with type_version==1 and BI_BITFIELDS compression have been seen
                $BMPheader .= fread($this->getid3->fp, 44);

                // BITMAPV4HEADER - [44 bytes] - http://msdn.microsoft.com/library/en-us/gdi/bitmaps_2k1e.asp
                // Win95+, WinNT4.0+
                // DWORD        bV4RedMask;
                // DWORD        bV4GreenMask;
                // DWORD        bV4BlueMask;
                // DWORD        bV4AlphaMask;
                // DWORD        bV4CSType;
                // CIEXYZTRIPLE bV4Endpoints;
                // DWORD        bV4GammaRed;
                // DWORD        bV4GammaGreen;
                // DWORD        bV4GammaBlue;
                $thisfile_bmp_header_raw['red_mask'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['green_mask'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['blue_mask'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['alpha_mask'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['cs_type'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['ciexyz_red'] = substr($BMPheader, $offset, 4);
                $offset += 4;
                $thisfile_bmp_header_raw['ciexyz_green'] = substr($BMPheader, $offset, 4);
                $offset += 4;
                $thisfile_bmp_header_raw['ciexyz_blue'] = substr($BMPheader, $offset, 4);
                $offset += 4;
                $thisfile_bmp_header_raw['gamma_red'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['gamma_green'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['gamma_blue'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;

                $thisfile_bmp_header['ciexyz_red'] = Helper::FixedPoint2_30(strrev($thisfile_bmp_header_raw['ciexyz_red']));
                $thisfile_bmp_header['ciexyz_green'] = Helper::FixedPoint2_30(strrev($thisfile_bmp_header_raw['ciexyz_green']));
                $thisfile_bmp_header['ciexyz_blue'] = Helper::FixedPoint2_30(strrev($thisfile_bmp_header_raw['ciexyz_blue']));
            }

            if ($thisfile_bmp['type_version'] >= 5) {
                $BMPheader .= fread($this->getid3->fp, 16);

                // BITMAPV5HEADER - [16 bytes] - http://msdn.microsoft.com/library/en-us/gdi/bitmaps_7c36.asp
                // Win98+, Win2000+
                // DWORD        bV5Intent;
                // DWORD        bV5ProfileData;
                // DWORD        bV5ProfileSize;
                // DWORD        bV5Reserved;
                $thisfile_bmp_header_raw['intent'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['profile_data_offset'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['profile_data_size'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
                $thisfile_bmp_header_raw['reserved3'] = Helper::LittleEndian2Int(substr($BMPheader, $offset, 4));
                $offset += 4;
            }
        } else {
            $info['error'][] = 'Unknown BMP format in header.';

            return false;
        }

        if ($this->ExtractPalette || $this->ExtractData) {
            $PaletteEntries = 0;
            if ($thisfile_bmp_header_raw['bits_per_pixel'] < 16) {
                $PaletteEntries = pow(2, $thisfile_bmp_header_raw['bits_per_pixel']);
            } elseif (isset($thisfile_bmp_header_raw['colors_used']) && ($thisfile_bmp_header_raw['colors_used'] > 0) && ($thisfile_bmp_header_raw['colors_used'] <= 256)) {
                $PaletteEntries = $thisfile_bmp_header_raw['colors_used'];
            }
            if ($PaletteEntries > 0) {
                $BMPpalette = fread($this->getid3->fp, 4 * $PaletteEntries);
                $paletteoffset = 0;
                for ($i = 0; $i < $PaletteEntries; ++$i) {
                    // RGBQUAD          - http://msdn.microsoft.com/library/en-us/gdi/bitmaps_5f8y.asp
                    // BYTE    rgbBlue;
                    // BYTE    rgbGreen;
                    // BYTE    rgbRed;
                    // BYTE    rgbReserved;
                    $blue = Helper::LittleEndian2Int(substr($BMPpalette, $paletteoffset++, 1));
                    $green = Helper::LittleEndian2Int(substr($BMPpalette, $paletteoffset++, 1));
                    $red = Helper::LittleEndian2Int(substr($BMPpalette, $paletteoffset++, 1));
                    if (($thisfile_bmp['type_os'] == 'OS/2') && ($thisfile_bmp['type_version'] == 1)) {
                        // no padding byte
                    } else {
                        ++$paletteoffset; // padding byte
                    }
                    $thisfile_bmp['palette'][$i] = (($red << 16) | ($green << 8) | $blue);
                }
            }
        }

        if ($this->ExtractData) {
            fseek($this->getid3->fp, $thisfile_bmp_header_raw['data_offset'], SEEK_SET);
            $RowByteLength = ceil(($thisfile_bmp_header_raw['width'] * ($thisfile_bmp_header_raw['bits_per_pixel'] / 8)) / 4) * 4; // round up to nearest DWORD boundry
            $BMPpixelData = fread($this->getid3->fp, $thisfile_bmp_header_raw['height'] * $RowByteLength);
            $pixeldataoffset = 0;
            $thisfile_bmp_header_raw['compression'] = (isset($thisfile_bmp_header_raw['compression']) ? $thisfile_bmp_header_raw['compression'] : '');
            switch ($thisfile_bmp_header_raw['compression']) {

                case 0: // BI_RGB
                    switch ($thisfile_bmp_header_raw['bits_per_pixel']) {
                        case 1:
                            for ($row = ($thisfile_bmp_header_raw['height'] - 1); $row >= 0; --$row) {
                                for ($col = 0; $col < $thisfile_bmp_header_raw['width']; $col = $col) {
                                    $paletteindexbyte = ord($BMPpixelData{$pixeldataoffset++});
                                    for ($i = 7; $i >= 0; --$i) {
                                        $paletteindex = ($paletteindexbyte & (0x01 << $i)) >> $i;
                                        $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$paletteindex];
                                        ++$col;
                                    }
                                }
                                while (($pixeldataoffset % 4) != 0) {
                                    // lines are padded to nearest DWORD
                                    ++$pixeldataoffset;
                                }
                            }
                            break;

                        case 4:
                            for ($row = ($thisfile_bmp_header_raw['height'] - 1); $row >= 0; --$row) {
                                for ($col = 0; $col < $thisfile_bmp_header_raw['width']; $col = $col) {
                                    $paletteindexbyte = ord($BMPpixelData{$pixeldataoffset++});
                                    for ($i = 1; $i >= 0; --$i) {
                                        $paletteindex = ($paletteindexbyte & (0x0F << (4 * $i))) >> (4 * $i);
                                        $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$paletteindex];
                                        ++$col;
                                    }
                                }
                                while (($pixeldataoffset % 4) != 0) {
                                    // lines are padded to nearest DWORD
                                    ++$pixeldataoffset;
                                }
                            }
                            break;

                        case 8:
                            for ($row = ($thisfile_bmp_header_raw['height'] - 1); $row >= 0; --$row) {
                                for ($col = 0; $col < $thisfile_bmp_header_raw['width']; ++$col) {
                                    $paletteindex = ord($BMPpixelData{$pixeldataoffset++});
                                    $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$paletteindex];
                                }
                                while (($pixeldataoffset % 4) != 0) {
                                    // lines are padded to nearest DWORD
                                    ++$pixeldataoffset;
                                }
                            }
                            break;

                        case 24:
                            for ($row = ($thisfile_bmp_header_raw['height'] - 1); $row >= 0; --$row) {
                                for ($col = 0; $col < $thisfile_bmp_header_raw['width']; ++$col) {
                                    $thisfile_bmp['data'][$row][$col] = (ord($BMPpixelData{$pixeldataoffset + 2}) << 16) | (ord($BMPpixelData{$pixeldataoffset + 1}) << 8) | ord($BMPpixelData{$pixeldataoffset});
                                    $pixeldataoffset += 3;
                                }
                                while (($pixeldataoffset % 4) != 0) {
                                    // lines are padded to nearest DWORD
                                    ++$pixeldataoffset;
                                }
                            }
                            break;

                        case 32:
                            for ($row = ($thisfile_bmp_header_raw['height'] - 1); $row >= 0; --$row) {
                                for ($col = 0; $col < $thisfile_bmp_header_raw['width']; ++$col) {
                                    $thisfile_bmp['data'][$row][$col] = (ord($BMPpixelData{$pixeldataoffset + 3}) << 24) | (ord($BMPpixelData{$pixeldataoffset + 2}) << 16) | (ord($BMPpixelData{$pixeldataoffset + 1}) << 8) | ord($BMPpixelData{$pixeldataoffset});
                                    $pixeldataoffset += 4;
                                }
                                while (($pixeldataoffset % 4) != 0) {
                                    // lines are padded to nearest DWORD
                                    ++$pixeldataoffset;
                                }
                            }
                            break;

                        case 16:
                            // ?
                            break;

                        default:
                            $info['error'][] = 'Unknown bits-per-pixel value ('.$thisfile_bmp_header_raw['bits_per_pixel'].') - cannot read pixel data';
                            break;
                    }
                    break;

                case 1: // BI_RLE8 - http://msdn.microsoft.com/library/en-us/gdi/bitmaps_6x0u.asp
                    switch ($thisfile_bmp_header_raw['bits_per_pixel']) {
                        case 8:
                            $pixelcounter = 0;
                            while ($pixeldataoffset < strlen($BMPpixelData)) {
                                $firstbyte = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                $secondbyte = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                if ($firstbyte == 0) {

                                    // escaped/absolute mode - the first byte of the pair can be set to zero to
                                    // indicate an escape character that denotes the end of a line, the end of
                                    // a bitmap, or a delta, depending on the value of the second byte.
                                    switch ($secondbyte) {
                                        case 0:
                                            // end of line
                                            // no need for special processing, just ignore
                                            break;

                                        case 1:
                                            // end of bitmap
                                            $pixeldataoffset = strlen($BMPpixelData); // force to exit loop just in case
                                            break;

                                        case 2:
                                            // delta - The 2 bytes following the escape contain unsigned values
                                            // indicating the horizontal and vertical offsets of the next pixel
                                            // from the current position.
                                            $colincrement = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                            $rowincrement = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                            $col = ($pixelcounter % $thisfile_bmp_header_raw['width']) + $colincrement;
                                            $row = ($thisfile_bmp_header_raw['height'] - 1 - (($pixelcounter - $col) / $thisfile_bmp_header_raw['width'])) - $rowincrement;
                                            $pixelcounter = ($row * $thisfile_bmp_header_raw['width']) + $col;
                                            break;

                                        default:
                                            // In absolute mode, the first byte is zero and the second byte is a
                                            // value in the range 03H through FFH. The second byte represents the
                                            // number of bytes that follow, each of which contains the color index
                                            // of a single pixel. Each run must be aligned on a word boundary.
                                            for ($i = 0; $i < $secondbyte; ++$i) {
                                                $paletteindex = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                                $col = $pixelcounter % $thisfile_bmp_header_raw['width'];
                                                $row = $thisfile_bmp_header_raw['height'] - 1 - (($pixelcounter - $col) / $thisfile_bmp_header_raw['width']);
                                                $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$paletteindex];
                                                ++$pixelcounter;
                                            }
                                            while (($pixeldataoffset % 2) != 0) {
                                                // Each run must be aligned on a word boundary.
                                                ++$pixeldataoffset;
                                            }
                                            break;
                                    }
                                } else {

                                    // encoded mode - the first byte specifies the number of consecutive pixels
                                    // to be drawn using the color index contained in the second byte.
                                    for ($i = 0; $i < $firstbyte; ++$i) {
                                        $col = $pixelcounter % $thisfile_bmp_header_raw['width'];
                                        $row = $thisfile_bmp_header_raw['height'] - 1 - (($pixelcounter - $col) / $thisfile_bmp_header_raw['width']);
                                        $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$secondbyte];
                                        ++$pixelcounter;
                                    }
                                }
                            }
                            break;

                        default:
                            $info['error'][] = 'Unknown bits-per-pixel value ('.$thisfile_bmp_header_raw['bits_per_pixel'].') - cannot read pixel data';
                            break;
                    }
                    break;

                case 2: // BI_RLE4 - http://msdn.microsoft.com/library/en-us/gdi/bitmaps_6x0u.asp
                    switch ($thisfile_bmp_header_raw['bits_per_pixel']) {
                        case 4:
                            $pixelcounter = 0;
                            while ($pixeldataoffset < strlen($BMPpixelData)) {
                                $firstbyte = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                $secondbyte = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                if ($firstbyte == 0) {

                                    // escaped/absolute mode - the first byte of the pair can be set to zero to
                                    // indicate an escape character that denotes the end of a line, the end of
                                    // a bitmap, or a delta, depending on the value of the second byte.
                                    switch ($secondbyte) {
                                        case 0:
                                            // end of line
                                            // no need for special processing, just ignore
                                            break;

                                        case 1:
                                            // end of bitmap
                                            $pixeldataoffset = strlen($BMPpixelData); // force to exit loop just in case
                                            break;

                                        case 2:
                                            // delta - The 2 bytes following the escape contain unsigned values
                                            // indicating the horizontal and vertical offsets of the next pixel
                                            // from the current position.
                                            $colincrement = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                            $rowincrement = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                            $col = ($pixelcounter % $thisfile_bmp_header_raw['width']) + $colincrement;
                                            $row = ($thisfile_bmp_header_raw['height'] - 1 - (($pixelcounter - $col) / $thisfile_bmp_header_raw['width'])) - $rowincrement;
                                            $pixelcounter = ($row * $thisfile_bmp_header_raw['width']) + $col;
                                            break;

                                        default:
                                            // In absolute mode, the first byte is zero. The second byte contains the number
                                            // of color indexes that follow. Subsequent bytes contain color indexes in their
                                            // high- and low-order 4 bits, one color index for each pixel. In absolute mode,
                                            // each run must be aligned on a word boundary.
                                            unset($paletteindexes);
                                            for ($i = 0; $i < ceil($secondbyte / 2); ++$i) {
                                                $paletteindexbyte = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset++, 1));
                                                $paletteindexes[] = ($paletteindexbyte & 0xF0) >> 4;
                                                $paletteindexes[] = ($paletteindexbyte & 0x0F);
                                            }
                                            while (($pixeldataoffset % 2) != 0) {
                                                // Each run must be aligned on a word boundary.
                                                ++$pixeldataoffset;
                                            }

                                            foreach ($paletteindexes as $paletteindex) {
                                                $col = $pixelcounter % $thisfile_bmp_header_raw['width'];
                                                $row = $thisfile_bmp_header_raw['height'] - 1 - (($pixelcounter - $col) / $thisfile_bmp_header_raw['width']);
                                                $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$paletteindex];
                                                ++$pixelcounter;
                                            }
                                            break;
                                    }
                                } else {

                                    // encoded mode - the first byte of the pair contains the number of pixels to be
                                    // drawn using the color indexes in the second byte. The second byte contains two
                                    // color indexes, one in its high-order 4 bits and one in its low-order 4 bits.
                                    // The first of the pixels is drawn using the color specified by the high-order
                                    // 4 bits, the second is drawn using the color in the low-order 4 bits, the third
                                    // is drawn using the color in the high-order 4 bits, and so on, until all the
                                    // pixels specified by the first byte have been drawn.
                                    $paletteindexes[0] = ($secondbyte & 0xF0) >> 4;
                                    $paletteindexes[1] = ($secondbyte & 0x0F);
                                    for ($i = 0; $i < $firstbyte; ++$i) {
                                        $col = $pixelcounter % $thisfile_bmp_header_raw['width'];
                                        $row = $thisfile_bmp_header_raw['height'] - 1 - (($pixelcounter - $col) / $thisfile_bmp_header_raw['width']);
                                        $thisfile_bmp['data'][$row][$col] = $thisfile_bmp['palette'][$paletteindexes[($i % 2)]];
                                        ++$pixelcounter;
                                    }
                                }
                            }
                            break;

                        default:
                            $info['error'][] = 'Unknown bits-per-pixel value ('.$thisfile_bmp_header_raw['bits_per_pixel'].') - cannot read pixel data';
                            break;
                    }
                    break;

                case 3: // BI_BITFIELDS
                    switch ($thisfile_bmp_header_raw['bits_per_pixel']) {
                        case 16:
                        case 32:
                            $redshift = 0;
                            $greenshift = 0;
                            $blueshift = 0;
                            while ((($thisfile_bmp_header_raw['red_mask'] >> $redshift) & 0x01) == 0) {
                                ++$redshift;
                            }
                            while ((($thisfile_bmp_header_raw['green_mask'] >> $greenshift) & 0x01) == 0) {
                                ++$greenshift;
                            }
                            while ((($thisfile_bmp_header_raw['blue_mask'] >> $blueshift) & 0x01) == 0) {
                                ++$blueshift;
                            }
                            for ($row = ($thisfile_bmp_header_raw['height'] - 1); $row >= 0; --$row) {
                                for ($col = 0; $col < $thisfile_bmp_header_raw['width']; ++$col) {
                                    $pixelvalue = Helper::LittleEndian2Int(substr($BMPpixelData, $pixeldataoffset, $thisfile_bmp_header_raw['bits_per_pixel'] / 8));
                                    $pixeldataoffset += $thisfile_bmp_header_raw['bits_per_pixel'] / 8;

                                    $red = intval(round(((($pixelvalue & $thisfile_bmp_header_raw['red_mask'])   >> $redshift)   / ($thisfile_bmp_header_raw['red_mask']   >> $redshift))   * 255));
                                    $green = intval(round(((($pixelvalue & $thisfile_bmp_header_raw['green_mask']) >> $greenshift) / ($thisfile_bmp_header_raw['green_mask'] >> $greenshift)) * 255));
                                    $blue = intval(round(((($pixelvalue & $thisfile_bmp_header_raw['blue_mask'])  >> $blueshift)  / ($thisfile_bmp_header_raw['blue_mask']  >> $blueshift))  * 255));
                                    $thisfile_bmp['data'][$row][$col] = (($red << 16) | ($green << 8) | ($blue));
                                }
                                while (($pixeldataoffset % 4) != 0) {
                                    // lines are padded to nearest DWORD
                                    ++$pixeldataoffset;
                                }
                            }
                            break;

                        default:
                            $info['error'][] = 'Unknown bits-per-pixel value ('.$thisfile_bmp_header_raw['bits_per_pixel'].') - cannot read pixel data';
                            break;
                    }
                    break;

                default: // unhandled compression type
                    $info['error'][] = 'Unknown/unhandled compression type value ('.$thisfile_bmp_header_raw['compression'].') - cannot decompress pixel data';
                    break;
            }
        }

        return true;
    }

    /**
     * @param  type    $BMPinfo
     *
     * @return bool
     */
    public function PlotBMP(&$BMPinfo)
    {
        $starttime = time();
        if (!isset($BMPinfo['bmp']['data']) || !is_array($BMPinfo['bmp']['data'])) {
            echo 'ERROR: no pixel data<BR>';

            return false;
        }
        set_time_limit(intval(round($BMPinfo['resolution_x'] * $BMPinfo['resolution_y'] / 10000)));
        if ($im = ImageCreateTrueColor($BMPinfo['resolution_x'], $BMPinfo['resolution_y'])) {
            for ($row = 0; $row < $BMPinfo['resolution_y']; ++$row) {
                for ($col = 0; $col < $BMPinfo['resolution_x']; ++$col) {
                    if (isset($BMPinfo['bmp']['data'][$row][$col])) {
                        $red = ($BMPinfo['bmp']['data'][$row][$col] & 0x00FF0000) >> 16;
                        $green = ($BMPinfo['bmp']['data'][$row][$col] & 0x0000FF00) >> 8;
                        $blue = ($BMPinfo['bmp']['data'][$row][$col] & 0x000000FF);
                        $pixelcolor = ImageColorAllocate($im, $red, $green, $blue);
                        ImageSetPixel($im, $col, $row, $pixelcolor);
                    } else {
                        //echo 'ERROR: no data for pixel '.$row.' x '.$col.'<BR>';
                        //return false;
                    }
                }
            }
            if (headers_sent()) {
                echo 'plotted '.($BMPinfo['resolution_x'] * $BMPinfo['resolution_y']).' pixels in '.(time() - $starttime).' seconds<BR>';
                ImageDestroy($im);
                exit;
            } else {
                header('Content-type: image/png');
                ImagePNG($im);
                ImageDestroy($im);

                return true;
            }
        }

        return false;
    }

    /**
     * @staticvar array $BMPcompressionWindowsLookup
     *
     * @param  type $compressionid
     *
     * @return type
     */
    public function BMPcompressionWindowsLookup($compressionid)
    {
        static $BMPcompressionWindowsLookup = array(
            0 => 'BI_RGB',
            1 => 'BI_RLE8',
            2 => 'BI_RLE4',
            3 => 'BI_BITFIELDS',
            4 => 'BI_JPEG',
            5 => 'BI_PNG',
        );

        return (isset($BMPcompressionWindowsLookup[$compressionid]) ? $BMPcompressionWindowsLookup[$compressionid] : 'invalid');
    }

    /**
     * @staticvar array $BMPcompressionOS2Lookup
     *
     * @param  type $compressionid
     *
     * @return type
     */
    public function BMPcompressionOS2Lookup($compressionid)
    {
        static $BMPcompressionOS2Lookup = array(
            0 => 'BI_RGB',
            1 => 'BI_RLE8',
            2 => 'BI_RLE4',
            3 => 'Huffman 1D',
            4 => 'BI_RLE24',
        );

        return (isset($BMPcompressionOS2Lookup[$compressionid]) ? $BMPcompressionOS2Lookup[$compressionid] : 'invalid');
    }
}
